.fourbox {
    width: 100%;
    text-align: center;
    padding-bottom: 100px;
}

.titone {
    font-size: 200px;
    font-weight: bold;
    color: #133572;
}

.tittwo {
    font-size: 36px;
}

.titthree {
    color: #878485;
}

.but {
    padding: 20px;
    box-sizing: border-box;
    font-weight: bold;
    color: white;
    border-radius: 5px;
    border: none;
    background-color: #25ABE1;
}
/* 响应350px */
@media screen and (max-width:351px) {
    .fourbox{
        padding-bottom: 50px;
    }
    .titone{
        font-size: 100px;
    }
    .tittwo{
        font-size: 18px;
    }
    .titthree{
        font-size: 8px;
    }
}